As important as a child’s order of birth may be, it is only an influence, not a final fact of life forever set in cement and unchangeable as far as how that child will turn out… Birth order information does not give the total psychological picture for anyone.*

Kelly Woo, "Birth order can say a lot about your family", http://archive.nandotimes.com/links/nandonext/volume5/birth.html 4/28/02; also Dr. Kevin Leman, The Birth Order Book: Why You Are the Way You Are quoted on the above listed site.
*Leman, quoted in Woo’s article